Glycolic acid-based deep eutectic solvents boosting co-production of xylo-oligomers and fermentable sugars from corncob and the related kinetic mechanism

Table 1 The composition and enzymatic hydrolysis of corncob residues treated by DESs

DES	Residues’ recovery (%)^a	Composition of residues (%)^b					Enzymatic hydrolysis of residues^c
		Cellulose	Xylan	AIL	ASL	Ash	Digestibility (%)
		Cellulose	Xylan	AIL	ASL	Ash	Cellulose xylan
Raw	–	31.3	23.8	18.1	2.1	1.7	45.2	23.0
GC(1:1)	72.6	42.4	23.2	12.8	1.5	2.4	61.0	39.9
GL(1:1)	71.4	43.2	20.9	12.5	1.5	2.8	81.1	69.2
GG (1:1)	46.2	58.2	11.1	16.9	0.8	2.6	93.2	77.8
GC(3:1)	48.5	58.1	12.7	18.7	1.1	0.4	84.6	82.5
GL(3:1)	55.2	51.3	17.6	18.0	1.3	1.3	80.5	71.5
GG(3:1)	45.1	64.5	8.7	10.9	0.7	1.6	81.0	95.5
GC(3:1) + FeCl₂.4H₂O	52.6	55.8	14.2	15.8	1.3	1.1	82.3	78.0
GL(3;1) + FeCl₂.4H₂O	45.6	63.1	9.7	10.0	0.7	1.2	72.9	90.1
GG(3:1) + FeCl₂.4H₂O	41.0	63.1	9.7	12.6	0.8	0.8	82.2	92.3
GC(3:1) + AlCl₃.6H₂O	47.7	56.2	2.2	26.1	0.4	1.3	58.2	65.1
GL(3:1) + AlCl₃.6H₂O	37.3	67.2	3.3	21.7	0.3	1.0	35.1	42.8
GG(3:1) + AlCl₃.6H₂O	41.5	59.6	1.8	21.6	0.5	0.6	43.0	41.3
GL(3:1) + MgCl₂.6H₂O	45.0	64.3	9.7	10.8	0.6	1.2	72.1	81.9

AIL acid-insoluble lignin, ASL acid-soluble lignin
^aCorncob was mixed with DESs in a 5wt% loading at 120 °C for 20 min, and then, the residues were washed by ethanol and water and freeze-dried before use. The data were present as mean value
^bDetermined via the NREL protocol (Sluiter et al. [38]). The results are expressed as a percentage of the residues. All data were showed as mean values with standard deviation less than 5%
^c20 mg of recovered corncob, 7 mL of citrate buffer (50 mmol L⁻¹, pH 4.8), and 8.3 U mL⁻¹ cellulase from Trichoderma reesei; 50 °C and 120 rpm. The polysaccharides’ digestibilities were calculated on the results of 21 h hydrolysis. The data were presented as mean value

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